Instruction manual

Page 1480 of 3156 FCC Compliance for DID Answer Supervision
553-3001-306 Standard 10.00 January 2002
Calls forwarded to Public Switched Network
Because it is uncertain whether or not the far end will return answer
supervision, the Meridian 1 uses the EOD and ODT timers. If the Meridian 1
has not detected the return of answer supervision upon timeout of the
outgoing CO trunk, the Meridian 1 sends pseudo-answer supervision to the
incoming DID trunk. This timer is set in LD 16 on a per-route basis. When a
CO trunk is configured, Meridian 1 software forces the value of SUPN to NO.
Consequently, Meridian 1 software does not expect the return of answer
supervision, and returns answer supervision in the following cases:
• The Meridian 1 receives answer supervision from the outgoing CO trunk
before the EOD or ODT timer of the outgoing route expires.
• The Meridian 1 does not receive answer supervision from the outgoing
trunk and the EOD or ODT timer of the outgoing route expires; pseudo-
answer supervision is generated.
Note: There are still some cases in which the SUPN value for CO trunks
is assigned to YES if the CO supports a reverse battery mechanism.
With FCC Compliance, a more stringent mechanism is introduced to apply
SUPN = NO in LD 14 to all CO trunks, even those configured as polarity
sensitive. Service-changeable EOD or ODT timers are always used for
incoming DID calls to enforce the return of answer supervision. In this case:
EOD = 128-19,968 milliseconds (ms) (default time is 13,952 ms), and
ODT = 256-16,128 ms (default time is 4,096 ms).
The EOD timer expires at 20 (20,000 ms) for FCC Compliance. For outgoing
DID calls, the EOD upper limit is 32,640 ms.
Not answered No
Busy signal No
Recorder signal No
DID call terminating status
Answer supervision
returned with FCC
Compliance